Injectable PrEP Frequently Asked Questions – Clinical
1. What is the time to protection of CAB-LA for injectable PrEP?
- Time to protection is not known with certainty for any form of PrEP.
- The available evidence based on animal models suggests 95% of people will achieve protective blood levels of CAB-LA 7 days after their first injection. Fifty percent of people will achieve protective blood levels 1 day after the first injection.
2. What is important to know about side effects of CAB-LA?
Injection site reactions (ISR) including pain, induration and swelling are the most common side effect and are more likely with the first few injections. In HPTN 083, 75% of participants in the CAB-LA arm who received at least one injection reported injection site pain. Clinicians should counsel patients around prevention and management of ISRs. Helpful strategies may include over-the-counter pain medication taken before or soon after an injection and/or application of a warm compress or heating pad to the injection site for 15-20 minutes following the injection.
3. Is an oral PrEP lead-in recommended before a patient receives the first CAB-LA injection?
- Given the delay many patients will experience obtaining CAB-LA, clinicians should consider a rapid initiation of oral PrEP for any patient requesting such protection – to delay PrEP initiation in these circumstances exposes patients to ongoing risk of HIV acquisition.
- If patients or providers have concerns about tolerability of CAB-LA, an oral lead-in with oral cabotegravir is a reasonable option.
- Clinically, a lead in of oral cabotegravir is not needed to achieve adequate blood levels of CAB-LA upon initiation of injections.
4. Can oral cabotegravir be used for oral PrEP prior to the first injection of CAB-LA?
- Oral cabotegravir tablets for this purpose – that is, explicitly as an HIV prevention strategy– is technically “off-label” according to the FDA package insert.
- FDA approved regimens to date for oral PrEP include generic TDF-FTC, or brand Truvada (TDF-FTC ) or Descovy (TAF-FTC)
5. Under what circumstances is oral cabotegravir approved for PrEP?
- To cover known delays or gaps in CAB-LA of up to two months, when the patient plans to miss an injection visit but wishes to continue CAB-LA as soon as interrupting factors are resolved.
See Appendix #3 ”Continuing CAB-LA following Planned or Unplanned Missed Injections” for recommendations
6. What if a patient wants to take the cabotegravir oral lead in for only one week, and then switch to the injectable form?
- The decision to administer a shorter course of oral cabotegravir lead-in (<28 days) to assess medication tolerability is up to the provider, in consultation with the patient.
7. If a patient has been maintained on injectable CAB-LA for, say, 4-6 months, but then needs to be transitioned back permanently to oral PrEP what is the best strategy?
- It would be reasonable to restart daily oral PrEP (TAF-FTC or TDF-FTC) 7 days prior to the date on which the next CAB-LA injection would have been administered, were the patient to have continued injectable PrEP.
8. For patients who want to stop CAB-LA injections but have ongoing risk for HIV infection, by when should they start taking oral PrEP?
- An alternative form of PrEP should be initiated within 2 months of the final CAB-LA injection. Ideally, 7 days prior to the date on which the next CAB-LA injection would have been administered.
9. How soon can a patient stop taking FDA approved oral PrEP regimens once they have received the 1st starter dose of CAB-LA?
- Available evidence suggests that seven days after the first CAB-LA injection would be the appropriate time to stop oral TDF-FTC or TAF-FTC.
10. What is meant by the CAB-LA “tail” and what risk does it relay to patients?
- There is a theoretical risk that if a CAB-LA patient is lost to follow-up, and experiences a very gradual waning of CAB-LA drug levels over many months (up to a year perhaps), not only is the patient at risk of acquiring HIV, but were the patient to contract HIV infection in this time period, the exposure to subtherapeutic blood levels of CAB-LA could induce drug resistance in the acquired virus – resistance to either cabotegravir, or perhaps the entire integrase inhibitor class of antiretrovirals more broadly.
11. Are there any gender differences of clinical or practical concern in the use of CAB-LA for HIV PrEP?
- According to available data, there are no gender differences in clinical or practical concerns in the use of CAB-LA for HIV PrEP. Therefore, neither counseling messages nor prescribing practices need to be varied based on the gender of the patient/client, or whether the patient/client is at risk of HIV infection due to vaginal versus anal sex/exposure, etc.
12. Are there any known drug-drug interactions between currently available oral PrEP medications and CAB-LA?
13. Are there any concerns about CAB-LA and gender affirming hormone therapy (GAHT)?
- Not according to available data.
14. Can a CAB-LA injection be administered into the lateral thigh as an alternative to the gluteal sites?
For reasons including patient preference, presence of gluteal implants, and management of injection site reactions (ISRs), clinicians have considered the appropriateness of administering CAB-LA at alternative anatomic sites. Data on administration of CAB-LA for PrEP in an alternative muscle group are not yet available but early pharmacokinetic data are promising. In a phase I treatment study, a single intramuscular dose of 600mg of cabotegravir and 900mg of rilpivirine administered in the in the lateral thigh achieved levels comparable to gluteal injections though a higher rate of ISRs was observed.
15. Is CAB-LA recommended for people who inject drugs?
Evidence suggested that oral tenofovir-based PrEP is effective in reducing risk of HIV acquisition in people who inject drugs (PWID) by an estimated 74%. (CDC) No data are yet available to support the use of injectable CAB-LA in those who inject drugs, despite the observation that an injectable agent might be preferred or more practical for use among those for whom daily pill adherence is challenging or who are unable to store oral medication. A small qualitative study found that injectable PrEP was acceptable among PWID. (Biello et al.) For PWID who also are at risk of HIV acquisition via sexual activity, oral or injectable PrEP are indicated for use.
16. Are there any data on CAB-LA efficacy and BMI?
- No, there are no data to support varying dosage amount or frequency based on weight or BMI.
- A longer needle length should be considered for persons who weigh >30 kg to ensure the medication reaches the gluteus muscle.
For additional clinical support, contact the National Clinician Consultation Center PrEP line:
(855) 448-7737 or (855) HIV-PrEP, Monday – Friday, 9 am – 8 pm ET.